Trowelling blade assemblies



Jan. 10, 1967 CAGNQ 3,296,946

TROWELLING BLADE AS SEMBLIES Filed 00x21, 1964 2 Sheets-Sheet 1 I NVENTOR. 1 01/6/ C '06 Ma United States Patent Office fifififidd PatentedJan. 10, 1967 3,296,946 TRQWELLING BLADE ASSEMELIEb Luigi tCagno,Hamilton, Ontario, Canada, assignor to Hamilton Float & Trowel Limited,Hamilton, Ontario, Canada Filed st. 21, 1964, Ser. No. 405,552 14Claims. (Cl. 94-45) This invention relates to trowelling bladeassemblies for use with a trowelling machine. More particularly, thisinvention relates to devices which enable trowelling blades to bequickly and easily attached to and detached from power trowellingmachines.

Trowelling machines, which also are known as concrete finishingmachines, are well known devices in widespread use. Typical of suchtrowelling machines are those described in the following United Statespatents:

2,605,683, August 5, 1952, H. S. Boulton; 2,689,507, September 21, 1954,H. E. McCrery; 2,888,863, June 2, 1959, G. G. Eisenbeis; 2,662,454,December 15, 1953, M. E. Whiteman.

It is common practice with present day trowelling machines to bolt thetrowelling blades to a blade holder, the latter being rotated by themotor of the machine. Thus, in aforementioned Patent 2,662,454, forexample, there is shown a trowelling machine having the usual threeblades with three bolts per blade being employed. When it is desired toreplace or reverse the trowelling blades, these being operations thatare performed quite frequently, it is necessary to unbolt these variousbolts, replace or reverse the blades, and finally bolt the blades inplace. This is a time-consuming operation in any event, but particularlywith machines that require removal of the guard ring extending aroundthe blades in order to replace or reverse the blades. In thisconnection, the guard often becomes bent, and in many cases it isdifficult to reinstall because of its bent condition.

Accordingly, in accordance with this invention there is provided adevice which permits the quick and easy removal, installation andreversal of trowelling blades, and which does not employ any fasteningdevices such as bolts.

In accordance with a preferred embodiment of this invention theaforementioned device is designed so as to permit the removal,installation or reversal of a trowelling blade without removal of theguard ring.

A further feature of a preferred embodiment of this invention is thatthe device is designed to prevent concrete from entering thereinto sothat the possibility of concrete interfering with the proper operationof the device is minimized.

In accordance with one embodiment of this invention there is provided atrowelling blade and attaching means for detachably attaching the sameto a trowelling machine. The trowelling blade has an upper surface, aworking surface opposite to the upper surface, two ends and two sides.The attaching means comprise a first part fixed to the blade and asecond part attachable with and detachable from the first part. One ofthese parts comprises two spaced-apart members with means maintainingthese members in fixed spaced-apart relationship with respect to eachother. The members each have a free edge and two ends. Formed in each ofthe members are two spaced-apart slots which commence at the free edgesof the members, have an entry portion extending away from the edge intothe member, and branch inwardly of the free edges towards both ends ofthe members to constitute two corresponding retaining portions thatpermit reversing end-for-end of the attachment of the blade to themachine. The other of the parts includes two pins with means holding thepins in fixed spaced-apart relationship with respect to each other. Whenthe parts are attached the pins extend between the members and into theslots in the members. Means are provided for securing the first part tothe upper surface of the blade. When the parts are attached theaforementioned members are positioned between the sides of the blade andextend generally towards the ends of the blade, whereby the branchedparts of the slots extend generally towards the ends of the blade.

The invention will become more apparent from the following detaileddescription taken in conjunction with the appended drawings in which:

FIGURE 1 is a perspective view showing a plurality of trowelling bladesmounted on blade holders, which, in turn, carry a guard ring, and whichare connected to a collar that is adapted to be driven by the drivingshaft of the motor of a trowelling machine;

FIGURE 2 is an exploded perspective view showing a trowelling bladeassembly embodying this invention;

FIGURES 3 and 4 are side views, in section, illustrating how to attach atrowelling blade embodying this invention to its blade holder; and

FIGURE 5 is a section taken along line 5-5 in FIG- URE 4.

Referring to FIGURE 1, there is shown a plurality of trowelling blades1%) which may be of the fioat blade, finishing blade or combinationblade type. Each of these blades is detachably connected to a generallyU-shaped inverted channel member 29 which, in turn, is securely fastenedto an arm 12. Arms 12 project outwardly from a collar 13 and aresecurely fastened thereto at 120 intervals for a three blade machine fora four blade machine) by any suitable means. Each of channel members 29is detachably connected to a guard ring 14- by any suitable means 15.

It will be appreciated, of course, that collar 13 is adapted to beconnected to the output shaft of the motor of a trowelling machine,whereby blades lit) may be rotated in a horizontal plane.

Referring now to FIGURES 25 inclusive, it will be seen that blade lid isgenerally rectangular in nature and has an upper surface 16, a workingsurface 17 disposed opposite to and therefore underneath upper surface16, two straight parallel sides 18 and 19 and two parallel ends 20 and21. It will be seen that the end portions of blade 10 are inclinedslightly upwardly.

Positioned centrally between the two sides 18 and 19 of blade 10 is agenerally U-shaped channel member 22. This member extends towards ends20 and 21 of blade 10 and indeed is perpendicular thereto. The base orcross-piece 23 of channel member 22 is secured to upper surface 16 ofblade 1%) by means of suitable fastening devices 24 such as rivets. Asbest shown in FIGURE 5, rivets 24 are disposed in a zig-zag pattern.This is an important feature of a preferred embodiment of thisinvention, since this disposition of rivets 24 has been found to makethe blade assembly more rigid than if a single row of fastening devicesare employed, as has been the case in the past, and consequently adiminishing in machine vibration has been realized. The fact that member22 is positioned centrally with respect to both the sides and ends ofblade 1%, particularly the former, rather than being offset, as has beenthe case in the past, also is an important feature of a preferredembodiment of this invention, as the force acting on blade 10 isconstrained to act along the centerline thereof rather than along a lineoffset from this centerline.

Member 22 includes two upstanding plates or side walls 25 and 26, eachof which has a free edge 25a and 26a respectively, these free edgesbeing spaced from upper surface 16 of blade 10. Provided in each of sidewalls 25 and 26 are two, spaced-apart, inverted, generally T- shapedslots 27. It will be seen that the foot or entry portion of each ofthese slots 27 commences at the free edge of its respective side Wall,extends away from the free edge and towards upper surface 16 of blade10, while the head or cross-piece of the T-shaped slot branches inwardlyof the free edge of its respective side walls towards the ends ofchannel member 22 and blade ends 20 and 21 to constitute two respectiveretaining portions.

At both ends of channel 22 detents 28 are provided in side Walls and 26.

As also shown in FIGURES 2-5 another generally U-shaped channel member29 is provided. This member has side walls or pates 3t) and 31, across-piece 32, and one end thereof is closed by an end wall 33. Aplurality of slots 34 of varying configuration are provided incrosspiece 32 so as to permit member 29 to be bolted or otherwiseaffixed to arm 12. The configuration of the slots is such that member 29may be bolted to the arms of different types of commercially availabletrowelling machines.

Extending between side walls 30 and 31 and fixed thereto by any suitablemeans, e.g. by heading, are pins 35, which, of course, are held in fixedspaced-apart relationship with respect to each other. The spacingbetween pins is the same as the spacing between corresponding points ofadjacent slots 27, as is best seen in FIGURE 3.

Fastened to end wall 33 by means of a nut and bolt is a spring clip 36.

Reference now will be made to FIGURES 3 s inclusive for a description ofhow trowelling blade 10 may be attached to or detached from channelmember 29, which, as aforementioned, is bolted to arm 12. In order tosecure blade 10 to the trowelling machine channel member 22 is insertedbetween side walls 30 and 31 of channel member 29 with pins 35 passinginto and through the entry portions of the respective slots 27. Blade 10and channel member 22 then are moved forwardly, i.e. to the left inFIGURES 3 and 4, so that pins 35 become positioned in the righthandretaining portions of slots 27. Blade 10 and channel member 22 thus areprevented from falling from channel member 29 when blade 10 is in itsnormal horizontal position, and centrifugal force, which throws blade 10outwardly, causes blade 10 to remain in the position shown in FIGURE 4when the machine is operating. If the trowelling machine is tilted,however, as when the trowelling machine is taken from job to job, blades10 may become accidentally detached by virtue of member 22 slidingrelative to member 29 and pins 35 slipping from slots 27. It is for thisreason that spring clip 36 is provided. This spring clip engages detents28, as shown in FIGURE 5, and prevents any sliding movement of blade 10and member 22 relative to channel member 29. Thus, spring clip 36detachably holds channel members 22 and 29 in fixed positions withrespect to each other insofar as sliding movement is concerned. Itshould be appreciated, however, that other means may be substituted forspring clip 36, and that spring clip 36 is not essential to theoperation of the device, but serves only the useful functionhereinbefore noted.

When it is desired to reverse blade 10, this can be done simply byreversing the aforementioned steps so as to remove the blade fromchannel member 29, turning the blade end for end, and re-attaching it tochannel member 29 in the aforementioned manner. Pins 35 then will bepositioned in the other ends of slots 27.

Aside from the ease with which blades may be changed or reversed usingapparatus embodying this invention, another important feature of theinvention is that crosspiece 32, extending as it does over the open topand free edges of channel member 22, covers the top of channel member22, while end wall 33 closes one open end of channel member 22, and sideWalls 30 and 31 extend outside of side walls 25 and 26 and cover slots27. In this way the possibility of concrete entering channel member 22and hindering the correct operation of the attaching device isminimized. While channel member 22 is open at one end thereof, this isunimportant as this is the end of the blade assembly positioned closestto the axis of rotation.

As noted in connection with FIGURE 1, guard ring 14 is detachablysecured to channel member 29. It therefore is apparent that guard ring14 need not be removed to install, replace or reverse blades.

While channel member 22 has been shown as being secured to blade 10, itshould be appreciated that channel members 22 and 29 may be reversed sothat the latter is secured to blade 10 and the former is secured to arm12.

It will be appreciated that it would not depart from this invention tomake channel member 22 in the form of a solid block having slots 27therein. The block should be of sufficient width to provide good bearingsurfaces for pins 35 and may have spaced side walls at either endthereof to accommodate detents 28.

What I claim as my invention is:

1. In a trowelling machine comprising a motor-driven member rotatableabout a generally vertical axis, and at least one trowelling bladecarrying arm carried by the member and extending radially therefromwhereby a blade carried by the arm is rotated in a generally horizontalplane upon rotation of the member and the arm about the said axis, theprovision of a trowelling blade and attaching means for detachablyattaching the same to the said rotatable arm; said trowelling bladehaving an upper surface, a working surface opposite to said uppersurface, two ends and two sides; said attaching means comprising anattaching portion secured to the upper surface of the trowelling bladeand a cooperating attaching portion secured to the said rotatable arm,one of said attaching portions comprising two spaced straddling membersand the other attaching portion being inter posed between said spacedstraddling members of the said one attaching portion, each memberattached to the blade being positioned between the sides of the bladeand extending generally towards the ends of the blade, one of the twoattaching portions having for each member thereof a free edge with twospaced slots formed therein, each slot commencing at said free edge ofthe associated member, having an entry portion extending into the memberaway from the free edge, and branching inwardly of the free edge towardsboth of the ends of the member to constitute two corresponding retainingportions and thereby permit reversing end-for-end of the attachment ofthe blade to the said rotatable arm, the other of said two attachingportions having secured thereto two transversely extending pins spacedapart a distance corresponding to the spacing of the said slots, thesaid pins being engaged in the said slot entry portions by movement ofthe trowelling blade toward the said arm and thereafter engaged inrespective retaining portions of the slots to retain the blade on thesaid arm by longitudinal sliding of the said two attaching portionsrelative to one another upon corresponding endwise movement of the bladerelative to the said arm.

2. The invention according to claim 1, and including means fordetachably holding the said two attaching portions in fixed positionrelative to one another, comprising a spring clip secured to one of theattaching portions and cooperating detent means on the other of theattaching portions.

3. In a trowelling machine comprising a motor-driven member rotatableabout a generally vertical axis, and at least one trowelling bladecarrying arm carried by the member and extending radially therefromwhereby a blade carried by the arm is rotated in a generally horizontalplane upon rotation of the member and the arm about the said axis, theprovision of a trowelling blade and attaching means for detachablyattaching the same to the said rotatable arm; said trowelling bladehaving an upper surface, a working surface opposite to said uppersurface, two ends and two sides; said attaching means comprising anattaching portion secured to the upper surface of the trowelling bladeand a cooperating attaching portion secured to the said rotatable arm,one of said attaching portions comprising two spaced straddling membersand the other attaching portion being interposed between said spacedstraddling members of the said one attaching portion, each member of theat taching portion secured to the blade being positioned between thesides of the blade, extending generally towards the ends of the bladeand having a free edge spaced from said blade upper surface with twospaced slots formed therein, each slot commencing at said free edge,having an entry portion extending into the member away from the freeedge, and branching inwardly of the free edge towards both of the endsof the member to constitute two corresponding retaining portions andthereby permit reversing end-for-end of the attachment of the blade tothe said rotatable arm, the said cooperating attaching portion securedto the said rotatable arm having secured thereto two transverselyextending pins spaced apart a distance corresponding to the spacing ofthe said slots, the said pins being engaged in the said slot entryportions by movement of the trowelling blade toward the rotatable armand thereafter engaged in respective retaining portions of the slots toretain the blade on the rotatable arm by longitudinal sliding of thesaid two attaching portions relative to one another upon correspondingendwise movement of the blade relative to the rotatable arm.

4. The invention according to claim 3, and including means fordetachably holding the said two attaching portions in fixed positionrelative to one another, comprising a spring clip secured to one of theattaching portions and cooperating detent means on the other of theattaching portions.

5. A trowelling blade sub-assembly for use in the invention according toclaim 3, comprising the said blade, and the said attaching portionsecured to and upstanding from the said upper surface of the blade, eachmember of the blade attaching portion having the said free edge with thesaid two spaced slots formed therein.

6. In a trowelling machine comprising a motor-driven member rotatableabout a generally vertical axis, and at least one trowelling bladecarrying arm carried by the member and extending radially therefromwhereby a blade carried by the arm is rotated in a generally hori-Zontal plane upon rotation of the member and the arm about the saidaxis, the provision of a trowelling blade and attaching means fordetachably attaching the same to the said rotatable arm; said trowellingblade having an upper surface, a working surface opposite to said uppersurface, two ends and two sides; said attaching means comprising anattaching portion secured to the upper surface of the trowelling bladeand a cooperating attaching portion secured to the said rotatable arm,said attaching portion secured to the said rotatable arm comprising twospaced straddling members upstanding from the rotatable arm, and thesaid attaching portion secured to the blade comprising at least onecooperating straddled member interposed between said spaced straddlingmembers and upstanding from the blade, each straddled member upstandingfrom the blade being positioned between the sides of the blade,extending generally towards the ends of the blade, and having for eachmember a free edge spaced from said blade upper surface with two spacedslots formed therein, each slot commencing at said free edge of theassociated member, having an entry portion extending into the memberaway from the free edge, and branching inwardly of the free edge towardsboth of the ends of the member to constitute two corresponding retainingportions and thereby permit reversing end-for-end of the attachment ofthe blade to the rotatable arm, the said straddling members upstandingfrom the rotatable arm having secured thereto and extending transverselybetween the two pins spaced apart a distance corresponding to thespacing of the said slots, the said pins being engaged in the said slotentry portions by movement of the trowelling blade toward the rotatablearm and thereafter engaged in respective retaining portions of the slotsto retain the blade on the rotatable arm by longitudinal sliding of thesaid two attaching portions relative to one another upon correspondingendwise movement of the blade relative to the rotatable arm.

7. The invention according to claim 6, and including means fordetachably holding the said two attaching portions in fixed positionrelative to one another, comprising a spring clip secured to one of theattaching portions and cooperating detent means on the other of theattaching portions.

8. The invention according to claim 6, wherein the said spacedstraddling sidewall members upstanding from the rotatable arm areconstituted by the upstanding arms of a generally U-shaped invertedchannel member having its crosspiece attached to the rotatable arm, theradially outer end of said channel member having an end wall extendingbetween said upstanding arms.

9. In a trowelling machine comprising a motor driven member rotatableabout a generally vertical axis, and at least one trowelling bladecarrying arm carried by the member and extending radially therefromwhereby a blade carried by the arm is rotated in a generally horizontalplane upon rotation of the member and the arm about the said axis, theprovision of a trowelling blade and attaching means for detachablyattaching the same to the said rotatable arm; said trowelling bladehaving an upper surface, a working surface opposite to said uppersurface, two ends and two sides; said attaching means comprising anattaching portion secured to the upper surface of the trowelling bladeand a cooperating attaching portion secured to the said rotatable arm,said attaching portion secured to the said rotatable arm, two spacedparallel straddling sidewall members upstanding from the rotatable armand the said attaching portion secured to the blade comprising twocooperating spaced parallel straddled sidewall members interposedbetween said straddling members and upstanding from the blade, thestraddled sidewall members being positioned between the sides of theblade, extending generally towards the end of the blade, and having foreach member a free edge spaced from said blade upper surface with twospaced slots formed therein, each slot commencing at said free edge ofthe associated member, having an entry portion extending into themembers away from the free edge, and branching inwardly of the free edgetowards both of the ends of the member to constitute two correspondingretaining portions and thereby permit reversing endfor-end of theattachment of the blade to the rotatable arm, the said straddlingmembers secured to the rotatable arm having secured thereto andextending transversely between them two pins spaced apart a distancecorresponding to the spacing of said slots, the said pins being engagedin the said slot entry portions by movement of the trowelling bladetoward the rotatable arm and thereafter engaged in respective retainingportions of the slots to retain the blade on the rotatable arm bylongitudinal sliding of the said two attaching portions relative to oneanother upon corresponding endwise movement of the blade relative to therotatable arm.

10. The invention according to claim 9, wherein the said spaced parallelstraddling sidewall members upstanding from the rotatable arm areconstituted by the upstanding arms of a generally U-shaped invertedchannel member having its crosspiece attached to the rotatable arm, andthe said spaced parallel straddled sidewall members are constituted bythe upstanding arms of another generally U-shaped channel member havingits crosspiece attached to the said upper surface of the blade.

11. The invention according to claim 10, and including means fordetachably holding the said two attaching portions in fixed positionrelative to one another, comprising a spring clip secured to one of theattaching portions and cooperating detent means on the other of theattaching portions.

12. A trowelling blade sub-assembly for use in the invention accordingto claim 9, comprising the said blade, and the said two cooperatingspaced parallel straddled sidewall members secured to and upstandingfrom the said upper surface of the blade, each said straddled memberhaving the said free edge and the said two spaced slots formed therein.

13. A trowelling blade sub-assembly for use in the invention accordingto claim 10, comprising the said blade, and the said generally U-shapedchannel member having its crosspiece attached to the said upper surfaceof the blade, so that its spaced parallel upstanding arms extend fromthe said blade upper surface, each arm having the said free edge and thesaid two spaced slots formed therein.

14. The invention according to claim 9, wherein the said spacedstraddling sidewall members upstanding from the rotatable arm areconstituted by the upstanding arms of a generally U-shaped invertedchannel member having its crosspiece attached to the rotatable arm, theradially outer end of the said channel member having an end wallextending between said upstanding arms.

References Cited by the Examiner UNITED STATES PATENTS 2,662,545 12/1953 Whiteman 9445 2,667,824 2/1954 McCrery 9445 2,878,730 3/1959 Barnes9445 FOREIGN PATENTS 691,732 7/1930 France.

References Cited by the Applicant UNITED STATES PATENTS 2,605,683 8/1952Boulton. 2,662,545 12/1953 Whiteman. 2,689,507 9/ 1954 McCrery.2,888,863 6/ 1959 Eisenbeis.

JACOB L. NACKENOFF, Primary Examiner.

1. IN A TROWELLING MACHINE COMPRISING A MOTOR-DRIVEN MEMBER ROTATABLEABOUT A GENERALLY VERTICAL AXIS, AND AT LEAST ONE TROWELLING BLADECARRYING ARM CARRIED BY THE MEMBER AND EXTENDING RADIALLY THEREFROMWHEREBY A BLADE CARRIED BY THE ARM IS ROTATED IN A GENERALLY HORIZONTALPLANE UPON ROTATION OF THE MEMBER AND THE ARM ABOUT THE SAID AXIS, THEPROVISION OF A TROWELLING BLADE AND ATTACHING MEANS FOR DETACHABLYATTACHING THE SAME TO THE SAID ROTATABLE ARM; SAID TROWELLING BLADEHAVING AN UPPER SURFACE, A WORKING SURFACE OPPOSITE TO SAID UPPERSURFACE TWO ENDS AND TWO SIDES; SAID ATTACHING MEANS COMPRISING ANATTACHING PORTION SECURED TO THE UPPER SURFACE OF THE TROWELLING BLADEAND A COOPERATING ATTACHING PORTION SECURED TO THE SAID ROTATABLE ARM,ONE OF SAID ATTACHING PORTIONS COMPRISING TWO SPACED STRADDLING MEMBERSAND THE OTHER ATTACHING PORTION BEING INTERPOSED BETWEEN SAID SPACEDSTRADDLING MEMBERS OF THE SAID ONE ATTACHING PORTION, EACH MEMBERATTACHED TO THE BLADE BEING POSITIONED BETWEEN THE SIDES OF THE BLADE,AND EXTENDING GENERALLY TOWARDS THE ENDS OF THE BLADE, ONE OF THE TWOATTACHING PORTIONS HAVING FOR EACH MEMBER THEREOF A FREE EDGE WITH TWOSPACED SLOTS FORMED THEREIN, EACH SLOT COMMENCING AT SAID FREE EDGE OFTHE ASSOCIATED MEMBER, HAVING AN ENTRY PORTION EXTENDING INTO THE MEMBERAWAY FROM THE FREE EDGE, AND BRANCHING INWARDLY OF THE FREE EDGE TOWARDSBOTH OF THE ENDS OF THE MEMBER TO CONSTITUTE TWO CORRESPONDING RETAININGPORTIONS AND THEREBY PERMIT REVERSING END-FOR-END OF THE ATTACHMENT OFTHE BLADE TO THE SAID ROTATABLE ARM, THE OTHER OF SAID TWO ATTACHINGPORTIONS HAVING SECURED THERE TO TWO TRANSVERSLY EXTENDING PINS SPACEDAPART A DISTANCE CORRESPONDING TO THE SPACING OF THE SAID SLOTS, THESAID PINS BEING ENGAGED IN THE SAID SLOT ENTRY PORTIONS BY MOVEMENT OFTHE TROWELLING BLADE TOWARD THE SAID ARM AND THEREAFTER ENGAGED INRESPECTIVE RETAINING PORTIONS OF THE SLOTS TO RETAIN THE BLADE ON THESAID ARM BY LONGITUDINAL SLIDING OF THE SAID TWO ATTACHING PORTIONSRELATIVE TO ONE ANOTHER UPON CORRESPONDING ENDWISE MOVEMENT OF THE BLADERELATIVE TO THE SAID ARM.